Toggle press



0. H. MAY

TOGGLE PRESS June 10, 1952 3 Sheets-Sheet 1 Filed Feb. 28, 1949 June 10, 1952 o. H. MAY 15005 TOGGLE PRESS I Filed Feb. 28, 1949 5 Sheets-Sheet 2 0. H- MAY TOGGLE PRESS June 10, 1952 3 Sheets-Sheet 5 Filed Feb. 28 1949 FIG.4.

Patented June 10, 1952 TOGGLE PRESS Otto Hermann May, Schwabisch Gmund, Germany Application February 28, 1949, Serial No. 78,768 In Switzerland August 24, 1948 11 Claims. 1

This invention relates to toggle presses. In former toggle presses, the toggles were ordinarily arranged so that the distance between the fixed and movable pins increased during the power strokes with a resulting force which was resisted by stresses in the :press frame above the table or platen. This resulted in the requirement for large cross-sectional areas and over-all dimensions of the presses, which considerably increased their weights, regardless of type, but particularly in cases of C -throated presses.

It is an object of the present invention to eliminate these disadvantages by arranging the toggle system in such a manner that the movable pin is free to approach or recede from the fulcrum pin during the power stroke, so as to relieve the press frame of the disadvantageous stresses. An especially advantageous form of my new toggle system is achieved by arranging it with a comparatively long bell crank forming a part of the toggle which may also be favorably positioned to clear the throat of the press so as to obtain a compact arrangement of the toggle linkage in the press frame, whereby the size of the press unit may be reduced.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application -of which will be indicated in the following claims.

In the following drawings, in which several of various possible embodiments of the invention are illustrated,

Fig. 1 is a vertical section taken through one form of my new press;

Fig. 2 is 'a skeleton diagram of the linkage employed in the Fig. 1 form of the invention shown in a retracted position of the ram;

Fig. 3 is a view similar to Fig. 2, showing an advanced position of the ram;

Fig. 4 is a perspective View showing another form of the invention; and,

Fig. 5 is a vertical section similar to Fig. 1, showing a third form of the invention.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now more particularly to Fig. 1, there is shown at numeral I a press frame carrying a table or platen 3 and having a guide 5 overhanging the table. The ram slide is indicated at 1. The linkage for operating the reciprocating slide 1 consists in a fulcrum pin 9 which is fixed for a given adjustment. This pin is carried in a slid- 2 ing block I I supported in the frame I, which'may be adjusted in position by means of a spindle I3, threaded through the frame at [5 and controlled by a handwheel l1. Depending from the fulcrum pin 9 is a toggle crank arm IS, the lower end of which carries a knee joint H. A connecting rod 23 joins the knee joint H with a crankpin 25 of a crank 21 which is rotary in a counterclockwise direction. Rotation of the crank 21 oscillates the arm [9 between the limits shown in Figs. 2 and 3. The crank 21is driven by means of a double-reduction gear train 29, 3 t, the usual flywheel '33 being employed on the main drive shaft.

The second link of the toggle mechanism is constituted by a bell crank 31, which has a relatively long arm 39 extending up from the knee joint 2 I. Its shorter arm 4| is laterally directed through openings 43 (in the frame) and 44 (in the ram slide) for connection with the ram slide I. Thus the member 31 arches over the throat T. The outer end of the short arm 4| is connected with the ram slide 1 by means of a connecting link 45 pinned at one end to the short arm 4!, as shown at 41, and at the other end to the ram slide, as shown at 49. At the juncture of its arms, the bell crank 31 is provided with a pin joint 5|, connecting it with a movable floating element or slide 53 constrained to move in a vertical guide 55 in the frame I.

Before describing the operation, it should be noted that the pin joint 5| is free to move up and down, and that any reactions from the work on the table 3 applied to the ram slide I tend to raise this point; but since its distance from the knee joint 2| is predetermined, as indicated by the dash line '51 (see Figs. 2 and 3'), a reaction is set up along the line 51, which line may be treated as an equivalent effective second link of the toggle mechanism. Reaction from the work on the table 3 is applied at 41. Thus the toggle system proper may be assumed to consist of the short toggle arm l9, pivoted at 9, the knee joint 2|, and the line 51 representing the second link of the toggle.

Fig. 2 shows the crankpin 25 at its forward dead center position. The arms l9 and 5'! are then at their maximum angle A. During motion from the forward to the rearward dead center (the latter shown in Fig. 3), the knee joint 2| moves backward on a circular path around the fulcrum pin 9. During this operation, the angle A between the eifective arms l9 and 51 diminishes to a small amount approaching coincidence as a limit (Fig. 3). During this action, the-pin 5| on slide block 53 moves first down a slight amount, and then up. During this motion of translation of the pin 5i, the bell crank 31 moves clockwise, thus causing the pin 41 to descend. At first, the downward velocity of the pin 5| acts in in an additive manner to increase the downward velocity of the pin 41, and as link 39 crosses coincidence with link I9, the upward velocity of the pin 5I subtracts from the downward velocity of pin 41. Hence the available force increases over a desirable period toward the end of the stroke. The upward reaction of the work applied to pin 41 is resisted along line 51, placing compression in the link I9, which delivers its force to the frame at point 9. Thus the primary actions and reactions are taken up by the part of the frame below the table 3, it being necessary only to deal with small forces applied laterally in the upper part of the frame in order to guide the block 53, the latter being otherwise free to move up and down.

The total stroke of the pin 41 is shown at a: (Fig. 3 related to Fig. 2). This stroke is considerably longer than it would be without the sidewise pivoted arrangement afforded by the bell crank 31. Moreover, the required shape of the bell crank for bringing about this advantage is itself advantageous in that it adapts itself to a convenient arrangement around and overreaching the press throat T. Adjustment of the position of the fulcrum pin 9 has its effect upon the effective velocity displacement diagram for the stroke 1:, and this is a convenience in adapting the press to particular requirements.

In Fig. 4 is shown another form of the invention, in which 59 indicates the frame, GI the table or platen, 53 the guide for the ram slide 65, the latter being held to an internal threaded extension 51 by means of an adjustable nut 69. The fulcrum pin, which is pivoted in the frame as indicated at 1|, forms the center of rotation for the toggle arm 13. The toggle arm is oscillated by means of a connecting rod pinned thereto at IN, and pinned at 11 between crank discs 19 which are rotary in the frame in bearings (see numeral 80). At 8| is shown the flywheel on the main drive shaft 83, which through a gear train 85 drives two pinions 81 that mesh with gears 89 cut in the peripheries of the crank discs 19. At 9| is indicated the bell crank, pivoted at 93 to a movable floating element or slide 95 which is constrained to move vertically in a guide 91 in the frame 59. The long arm of the bell crank is shown at 99 and its lower end is pivoted at the knee joint to the toggle arm I3. Thus the pivoted point I02 between the bell crank 9I and the toggle arm is displaced from the pivot point IOI between the toggle arm 13 and the connecting rod 15. This reduces some complications that arise in making a three-way pin joint.

The short arm I03 of the bell crank 9| reaches through suitable slots in the frame and ram slide 65. These slots are not shown in Fig. 4 because they are analogous to similar slots already described in the case of Fig. 1. This short arm is linked to the member 61 of the ram slide 65 through pin joints I05 and link I01.

Itwill be understood in connection with Fig. 4 that there are two lateral components to the link I01, link I3, pivot 1 I, bearing 93, slide 95 and guide 91, those on the near side of the drawing being shown in full. Those on the far side are not completely shown in order not to complicate the drawing unnecessarily, and are mere dupli- 4 cates, as will be understood by those skilled in the art.

The operation of the invention shown in Fig. 4 is similar to that already described in connection with Fig. 1, except that the effective line of pull on pin I05 is directed toward pin I02, instead of toward pin IOI. The line of tension is indicated at I09. This shortens the stroke of the ram slide 65 for a given throw of the crankpin 11 and simplifies the joint construction as above stated.

Referring to Fig. 5, there is shown another form of the invention, wherein the toggle linkage, instead of being folded back upon itself, is in an extended form. In this case the frame of the press is shown at I I I, having a table or platen H3, a ram guide H5 and a ram slide III. The fulcrum pin is shown at H9 and is carried in a slide I2I (guided with respect to the frame). This slide may be adjusted to different positions by means of a shaft I23 threaded through the frame at I25 and controlled from a handwheel I21 to vary the stroke of the ram slide. The shorter toggle arm is shown at I29 extending up toward the table, being linked at knee joint I3I to the connecting rod I33 which is pinned at I35 to the crank disc 131. The crank disc I31 is driven from the main shaft I39 through a gear train consisting of a worm-and-wheel combination MI, and a spur gear combination I43. The usual flywheel is shown at I45. By rotating the crank disc I31, the toggle arm I29 is oscillated around the fixed center I I9. Above the table I I3, the arrangement is as already described in connection with the other forms. The bell crank is shown at I41, having a long downward extending arm I49 connected with the knee joint I3I, and having a short lateral arm I5I connected with the ram slide II1 through pin joints I52, I53 and the intermediate link I55. The short arm I5I passes through openings I51 and I59 in the frame and ram slide, respectively.

The ram slide H1 is in its uppermost position when the crankpin I35 reaches its right-hand dead center. In practice, the pin joints H9, I3I and I52 are not driven into the straight line I5I joint I3I remaining on the crank side of the line. During operation, the crank drive I31, I33 retracts the joint I3I until greatest displacement of it to the left is achieved upon reaching the opposite dead center. The pin joints H9 and I52 thus approach one another, thereby effecting a downward motion of the ram slide II1 toward the table 'I I3, which provides the power stroke. The tension is along the line I6 I, which of course changes its position as the movement proceeds. This form of the invention differs somewhat from the other forms in that the greatest force is achieved during initial parts of the stroke of the ram slide, thereafter decreasing and then rising somewhat at the end of the stroke. In the forms of the invention shown in Figs. 1-4, the greatest force is achieved toward the end of the stroke. The action of the constructions of Figs. l-4 is better for some purposes, as for example, in coining, while the action of the Fig. 5 form is better in other instances, such as, for example, cutting, shearing or punching, wherein not so great a force is required after initial shear has taken place.

In all forms of the invention, all parts of the toggle system above the table of the press float with respect to the frame, being bodily supported upon the knee joint 2I (Fig. 1), I02 (Fig. 4) or I3I (Fig. 5). This floating is allowed by the movable floating element or slide. In all cases, the

adomase fl L joint- 9 Y I), N (Fig; '9 ori'iil a (mg 5)?"supports'the kneejcintfroni the-frame Thus the-entire toggle system; including"therannslide; floats-with respect-tothe frame-above or: beyond the-platen;

All forms of the invention have -the-advantage thatthe greatest forces in the frame are' carried below' the table H3; thus relieving the-frame around the throat (whether C -sliaped on otherwiser of large'forcesi Large forces,- particularly inic shaped-throats; produce-high stressesunless inordinately large amounts of metal are pro--- vided. Moreover, it isdifficult to==make d-shaped throats rigid enough to prevent tool misalignment, butby' relievingthen-shape around the throat of"large"forces=', thethro'ats of the present" machine's-may be made more rigid though lighter in weight;

Return-mg tothe-m'atter of the forces involved in the framebelowthe table; taking Fig; I for an example, the downward force of the work on thetableis applied to theframe. 'I-heprimary reaction is upward on the fulcrum pin- 9 and hence uponthe' frame in this region; Sincethese forces are approximately opposite, the problem of a designer is primarily toprovidea sufficient frame section in shear below and just-to theleft of the tables which is a relatively simple matter to deal with:

By means of the present invention; the press may bemade-much lighter for equal strength and capacity. For example; for comparahle presses of substantially equalcapacities and stroke, the weight of press made according to the present invention is of the order" of one-third of the weight of the former presses, and. much more compact.

In view of the above, it will be: seen. that the several objects of the invention areachieved and other advantageous results: attained.

As many changes could be made in the above constructions. without departing from the scope of the invention; it is intended" that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A toggle press comprising a frame having a platen and a ram slide on opposite sides of a work gap, a toggle linkage having a fulcrum located in the frame toward one side of the work gap, said toggle linkage comprising a link pivoted on said fulcrum and providing a swinging knee joint, a link having one end pivoted at said knee joint and extending past the work gap, and a pivot carried by said last-named link having a sliding connection with the frame on the ramslide side of the work gap, said last-named link also having an operative connection with the ram slide and being in the form of a bell crank, one arm of which passes the work gap and the other arm of which arches thereover.

2. A toggle press comprising a frame having a platen, a toggle linkage having a fulcrum located in the frame in the region of the platen, said toggle linkage comprising a link pivoted on said fulcrum and providing a swinging knee joint, a ram slide located to reciprocate opposite the platen, a link having one end pivoted at said knee joint and extending past the platen, a pivot carried by said last-named link having a sliding connection with the frame, said last-named link also having an operative connection with the ram slide, and a driving linkage for oscillating said toggle linkage, said driving linkage having connectionswith the-parts ofthe frame on the side.

age-having afulcrum located in -the frame toward one side of thethroat; said toggle-linkage comprising a link" pivoted on-sa-id fulcrum and providing aknee joint also onsaid one side of the throat, a ram" slide located on the opposite side ofthe throat, a link-in the general form of abell 'cranki having onearm pivoted'atsaid knee jointand extending past thethroat, the other arm ofthe-bell-crankoverhanging the throat andhaving an operative connection with the ram slide, and a pivot carried by theb'ell crank havinga slidi'ngconnection with the frame;

4;- A toggl'epress comprisinga frame-formed to provide arropen C-shapedthroat, a togglelinkagehaving' a fulcrum located? in the frame toward: one side'of the throat, said toggle linkage comprising a link pivoted on said fulcrum" andproviding a knee; joint also on said one side of the throat, a'p'ower'mech-anism located in theframe also on saidoneside of the throat and adapted to oscillate said link, a ram slide located onthe opposite side of the throat; a link in the general form of a bell' crank having one arm pivoted at said knee joint and" extending past the throat, the otherarm of the-'bell crank overhanging the throatand having an operative connection with the ram slide; and; a pivot carried bythe bell crankhaving aslidingiconnection with the'frame, said pivot having a? position on the bell" crank int'ermediat'eits two arm's said sliding connection with; the frame being" on said opposite side; oi" the throat;

5; A- toggle press comprising a frame formed: to" provide an" open, c-shapedthroat, a toggle: linkage having a fulcrum" locatedthe frametoward one side of the throat, saidtoggle' linkage comprising a link. pivotedon said fulcrum and providing a knee jointalso on said one side of the throat a: power mechanism located: in the frame also onzs'aid one side of the throat and adapted to oscillate said link, a ram slide located on the opposite side of the throat, a link in the general form of a bell crank having one arm pivoted at said knee joint and extending past the throat, the other arm of the bell crank overhanging the throat and having an operative connection with the ram slide, and a pivot carried by the bell crank having a sliding connection with the frame, said pivot having a position on the bell crank intermediate its two arms, said sliding connection with the frame being on said opposite side of the throat, and mechanism for adjusting the fulcrum transversely of said frame.

6. A toggle press comprising a frame formed to provide an open 'C-shaped throat including a platen, a toggle linkage having a fulcrum located in the frame toward one side of the throat, said toggle linkage comprising a link pivoted on said fulcrum and extending away from the platen and providing a knee joint also on said one side of the throat, a driving mechanism consisting of a crank and connecting rod between it and the knee joint and located on said one side of the throat, a ram slide located on the opposite side of the throat, and a link in the general form of a bell crank having one arm pivoted at said knee joint and directed so as to extend past the throat where it is provided with a pivoted slide connection with the frame, the other arm of the bell crank overhanging the throat where it is provided with an operative connection with the ram slide.

7. A toggle press comprising a frame formed to provide an open C-shaped throat including a platen, a toggle linkage having a fulcrum located in the frame toward one side of the throat, said toggle linkage comprising a link pivoted on said fulcrum and extending in a direction generally toward the platen and providing a knee joint also on said one side of the throat, a driving mechanism consisting of a crank and connecting rod between it and the knee joint and located on said one side of the throat, a ram slide located on the opposite side of the throat, and a link in the general form of a bell crank having one arm pivoted at said knee joint and directed so as to extend past the throat where it is provided with a pivoted slide connection with the frame, the other arm of the bell crank overhanging the throat where it is provided with an operative connection with the ram slide.

8. A toggle press comprising a frame formed to provide an open C-shaped throat including a platen, a toggle linkage having a fulcrum located in the frame toward one side of the throat, said toggle linkage comprising a link pivoted on said fulcrum providing a knee joint also on said one side of the throat, a driving mechanism consisting of a crank and connecting rod between it and the knee joint and located on said one side of the throat and extending away from its closed side, a ram slide located on the opposite side of the throat, and a link in the general form of a bell crank having one arm pivoted at said knee joint and directed so as to extend past the throat on its closed side where the bell crank is provided with a pivoted slide connection with the frame, the other arm of the bell crank overhanging the throat where it is provided with an operative connection with the ram slide.

9, A toggle press comprising a frame formed to provide an open C-shaped throat including a platen, a toggle linkage having a fulcrum located in the frame toward one side of the throat, said toggle linkage comprising a link pivoted on said fulcrum providing a knee joint-also on said one side of the throat, a driving mechanism consisting of a crank and connecting rod between it and another pivot joint on said link and located on said one side of the throat, a ram slide located on the opposite side of the throat, and a link in the general form of a. bell crank having one arm pivoted at said knee joint and directed so as to extend past the throat where it is provided with a pivoted slide connection with the frame, the other arm of the bell crank overhanging the throat where it is provided with an operative link connection with the ram slide.

10. A toggle press comprising a frame-having a platen and a ram slide on opposite sides of a work gap, a fulcrum located on the frame, an

oscillating toggle arm extending from said fulcrum and providing a knee joint, a rotary crank,

a connectin link between said crank and said toggle arm adapted upon rotation of the crank to oscillate said toggle arm and said knee joint, a substantially vertically movable floating element having a freely movable connection with the frame, and a toggle link pivoted to said knee joint, said toggle link having a connection with said movable element and having an additional operative connection with the ram slide.

11. Apparatus made according to claim 10, in which, considering the ram slide as vertical, the fulcrum and the knee joint are at points not higher than the top of the gap, and in which said movable element and said operative connection are located at points not lower than the bottom of the gap.

OTTO HERMANN MAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 517,064 Ralston Mar. 27, 1894. 976,877 Heinss Nov. 29, 1910 

